This invention relates to unit bearing motors, and more particularly to a removable winding cover for such a unit bearing motor.
Reference may be made to the co-assigned U.S. Pat. No. 4,209,722, issued June 24, 1980, which discloses, in detail, the construction of a typical unit bearing motor. Such unit bearing motors are oftentimes utilized as the condenser fan motor in a home refrigerator or the like.
Typically, in a unit bearing motor, such as shown in the above-noted U.S. Pat. No. 4,209,722, a cast endshield has an integral central boss which extends at least part-way into the stator. The rotor shaft of the rotor is journaled within suitable bushings carried within this boss such that a single bearing mounts and rotatably journals the rotor within the stator. The endshield encloses and protects one side of the windings of the motor and a unitary, sheet metal cover is pressed onto an outer surface of the stator core which extends axially beyond the endshield so as to enclose and protect the other side of the windings of the motor.
In the manufacture of unit bearing motors, it is sometimes necessary to remove the winding cover from the motor so as to permit repair of certain defects uncovered during quality control testing of the assembled motors. However, with motors constructed as shown in the above-noted U.S. Pat. No. 4,209,722, the removal of the winding covers which have been pressed onto the core oftentimes damaged components within the motor or the cover, due to the tight fit between the motor cover and the outer surface of the stator core. In addition, it was not possible to remove the winding cover in the field, and thus the prior art unit bearing motors were not readily field repairable.
The inability of being able to remove a prior art winding cover from a unit bearing motor without damage to either the cover or the stator assembly has been a long-standing problem. Each year, the assignee of this invention has found it necessary to rework tens of thousands of such unit bearing motors during the assembly and quality control testing thereof. Generally, the prior art press-fit winding cover, such as shown in the above-noted U.S. Pat. No. 4,209,722, is damaged during removal, and must be thrown away after removal. In addition, a relatively high percentage of these reworked motors experience damage to their stators during disassembly due to the difficulty of removing the winding cover, and these motors with damaged stators are also scrapped.